<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
     

        .top {
            background-color: gray;
       
         height: 100px;

        }

        .center {
           
            
            display: flex;
            justify-content: space-between;
        }

        .center1 {
            width: 258px;
            height: 100vh;
            background-color: green;
            justify-content: center;
            align-items: center;
           
        }

        .center2 {
            width: 318px;
            height: 100vh;
            background-color: #fff;
            justify-content: center;
            align-items: center;
        }

        .center3 {
            width: 288px;
            height: 100vh;
            background-color: purple;
            justify-content: center;
            align-items: center;

        }
        .center1::before{
    content: "左侧";
}.center2::before{
    content: "中侧";
}.center3::before{
    content: "右侧";
}
        @media screen and (max-width:500px) {

            .center{
                display: flex;
                flex-direction: column;
                justify-content: flex-end;
            }
           
        .center1 {
            width: 100vw;
            height: 626px;
            background-color: #fff;
           
        }
.center1::before{
    content: "中间";
}.center2::before{
    content: "左侧";
}.center3::before{
    content: "右侧";
}
        .center2 {
            width: 100vw;
            height: 566px;
            background-color: green;
          
        }

        .center3 {
            width: 100vw;
            height: 566px;
            background-color: purple;

        }
        }
    </style>
</head>

<body>
    <div class="all">
        <div class="top">一天到晚游泳的鱼</div>
        <div class="center">
            <div class="center1"></div>
            <div class="center2"></div>
            <div class="center3"></div>
        </div>
        <div class="botoom"></div>
    </div>
</body>

</html>